Identification and characterization of a novel and specific inhibitor of the ataxia-telangiectasia mutated kinase ATM
Identification and characterization of a novel and specific inhibitor of the ataxia-telangiectasia mutated kinase ATM
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DOI：
10.1158/0008-5472.can-04-2727
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发表时间：
2004-12-15
期刊：
影响因子：
11.2
通讯作者：
Smith, GCM
中科院分区：
文献类型：
--
作者：
Hickson, I;Yan, Z;Smith, GCM
丝氨酸/苏氨酸蛋白激酶ATM通过磷酸化下游靶点，如p53、CHK2、NBS1和BRCA1，向细胞周期和DNA修复组分发出信号。ATM突变发生在人类常染色体隐性遗传病共济失调-毛细血管扩张症中，其特征是对电离辐射过敏，并且在诱导DNA双链断裂后细胞无法阻止细胞周期。因此，有人提出，ATM抑制会引起细胞无线电和化学致敏。通过筛选磷脂酰肌醇3′-激酶样激酶家族的小分子化合物文库，我们发现了一种atp竞争抑制剂，2-morpholin-4-yl-6- thianthen -1-yl-pyran-4-one (KU-55933)，其抑制ATM的IC50为13 nmol/L， Ki为2.2 nmol/L。KU-55933对其他磷脂酰肌醇3'-激酶样激酶具有特异性抑制作用。KU-55933对ATM的细胞抑制作用被证明是通过电离辐射依赖的一系列ATM靶点磷酸化的消融，包括p53、gammaH2AX、NBS1和SMC1。KU-55933对紫外光DNA损伤诱导的细胞磷酸化事件没有抑制作用。细胞暴露于KU-55933导致对电离辐射的细胞毒性作用和对DNA双链断裂诱导化疗药物，依托泊苷，阿霉素和喜树碱的显着敏化。KU-55933对ATM的抑制也引起电离辐射诱导的细胞周期阻滞的损失。相比之下，KU-55933不会增强电离辐射对失调性毛细血管扩张细胞的细胞毒性作用，也不会影响DNA损伤后的细胞周期谱。我们得出结论，KU-55933是一种新的、特异性的、有效的ATM激酶抑制剂。
The serine/threonine protein kinase ATM signals to cell cycle and DNA repair components by phosphorylating downstream targets such as p53, CHK2, NBS1, and BRCA1. Mutation of ATM occurs in the human autosomal recessive disorder ataxia-telangiectasia, which is characterized by hypersensitivity to ionizing radiation and a failure of cells to arrest the cell cycle after the induction of DNA double-strand breaks. It has thus been proposed that ATM inhibition would cause cellular radio- and chemosensitization. Through screening a small molecule compound library developed for the phosphatidylinositol 3'-kinase-like kinase family, we identified an ATP-competitive inhibitor, 2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one (KU-55933), that inhibits ATM with an IC50 of 13 nmol/L and a Ki of 2.2 nmol/L. KU-55933 shows specificity with respect to inhibition of other phosphatidylinositol 3'-kinase-like kinases. Cellular inhibition of ATM by KU-55933 was demonstrated by the ablation of ionizing radiation-dependent phosphorylation of a range of ATM targets, including p53, gammaH2AX, NBS1, and SMC1. KU-55933 did not show inhibition of UV light DNA damage induced cellular phosphorylation events. Exposure of cells to KU-55933 resulted in a significant sensitization to the cytotoxic effects of ionizing radiation and to the DNA double-strand break-inducing chemotherapeutic agents, etoposide, doxorubicin, and camptothecin. Inhibition of ATM by KU-55933 also caused a loss of ionizing radiation-induced cell cycle arrest. By contrast, KU-55933 did not potentiate the cytotoxic effects of ionizing radiation on ataxia-telangiectasia cells, nor did it affect their cell cycle profile after DNA damage. We conclude that KU-55933 is a novel, specific, and potent inhibitor of the ATM kinase.